Whenever I boil chickpeas aka garbanzo beans, I usually scoop up and discard the foam that rises to the top of the pot. Is there any reason other than for aesthetics to remove the foam?
As a secondary question, has anyone tried using this foam as an ingredient? It seems like it contains a lot of protein because the bubbles are stiff and resistant to popping. The flavor is pleasant, and the texture is unique.
According to a quick search it appears that your notion about it being protein-based is correct. Most of the recipes I've seen say to skim it; the above-linked site says that adding a little oil will keep the foam down.
I personally wouldn't do anything with it as an ingredient unless I had a truly massive amount of it to experiment with--I don't know enough about the properties to make anything other than wild guesses about how it would work. The only similar material I can think of would be beaten egg whites, but unless you were desperate for a vegan alternative and were already boiling up vats full of chickpeas I'd just use the eggwhites.
A little late answer but one time I experimented with using the foam from cooked chickpeas. I mixed it with a little sugar, put it on a pan and popped it in the oven. It hardened up, browned and came out somewhat similar to a meringue with a nice sweet taste, but I waited a bit too long, so the foam wasn't quite as fluffy as beaten egg whites. I'm not sure how you would get enough or be able to use it fast enough before the foam starts deteriorating.
I find that occasionally there will be chaff in beans after boiling them. As a result, after draining I rinse the beans before using them, which in turn rinses away the foam. If you scoop away the foam I suppose that is one way to try to experiment with it; but if you're planning on draining without rinsing I would advise against it as you may end up with chaff in your hummus.
